A US jury has recommended that a Pakistani man be executed for murdering two CIA employees outside the agency's headquarters in Virginia in 1993.

Security fears around the case were heightened on Wednesday when four American nationals were shot dead in Pakistan after Aimal Khan Kansi was convicted of murder.

Pakistani police believe the killing of four employees of a Texas-based oil company may have been a direct response to the conviction of Kansi in the Virginia courtroom on Monday.

The group that claimed responsibility for the killings in Karachi said it would mount further attacks if Kansi, 33, was sentenced to death.

American embassies in Pakistan and elsewhere have warned US nationals to take special precautions. The Pakistani government has vowed to do everything in its power to find those responsible for the attack, which came at a particularly sensitive time - just days before a visit to Pakistan from the US Secretary of State, Madeleine Albright.

The judge ordered the jurors to be sequestered after the killings to shield them from news coverage. They were also kept under armed guard.

The jury deliberated for seven hours on whether to recommend the death sentence or life in prison. It had earlier heard graphic descriptions of the killings of two CIA employees, and accounts of Kansi's political motives.

Three other men were wounded when Kansi opened fire with an AK-47 on cars at a stop light in morning traffic.

Kansi was on the run for four years

Kansi bought a one-way ticket to Pakistan hours after the shooting and left the next day. He eluded a global manhunt for four and a half years. The FBI tracked him to a Pakistani hotel and arrested him.

Kansi showed no emotion as the verdict was delivered. He must wait until January to find out if the judge will formally impose the death penalty.

According to testimony, he confessed to the shootings repeatedly since FBI agents captured him in June. He is reported to have called the attack vengeance for American interference in Muslim countries. He did not testify during the trial.